Minecraft for Vita will arrive in August according to a new post up on Mojang's site. It will include all the features from the most recent PlayStation 3 version, including online play on Vita. If you have recently brought Minecraft: Playstation 3 Edition from PSN you’ll be able to upgrade for free.
Saves are transferable between the Playstation 3 and Vita versions of Minecraft. You will be able to craft at home on your Playstation 3, then continue on the bus/toilet with your Playstation Vita.
All of the DLC you’ve purchased for Minecraft: Playstation 3 Edition will work on Playstation 3 + Vita Edition.